For wood a rough guesstimate is 1/2T per rated kW per annum, so if your heating requirement is 20kW you'd need 10Tonnes of wood per annum (regardless that you would probably install a 32kW boiler). I'd look in to deciduous coppice feeding a wood chip boiler.

try http://handbooks.btcv.org.uk/handbooks/content/section/3767

Posted By: agu2 acres is about the same as 6 tonnes of coal or 4000 litres of kerosine oil

Is that the yearly product of 2 acres equiv. to 6T/4000l per annum?

goes to show that at 1 acre per person in the UK (including all infrastructure, coastline mountains and generally crap agricultural land, we are a tad over populated at present!

Posted By: joe.eIf you do grow willow, you don't actually need a biomass boiler; you can grow it on a three or four year rotation, chop it up into logs and use woodburning stoves.

You'll need quite a bit of land (about 2 hectares for self-sufficiency) and it takes a while for the first crop to be harvested. I know that willow and then ash are fast growing, but my ash coppice is just coming into its third year and it's still saplings, effectively. I don't think that willow is so much quicker that it produces burnable logs in three years - I could see it getting to maybe a couple of inches at the stem...? Perhaps there are varieties that can do better than this.

Dan

joe.e
think you will find that everybody else is talking in acres rather than your hectares. think it is about 2 acres to a hectare - ish ???
Must check on that.

Yes, from scratch it takes a lot longer - maybe five or ten years for the tree to get established. But as I say, I'm sure that 2 hectares (=about 5 acres) of established mixed coppice and standards would produce a lot more wood than one household could get through.

One of the other minor advantages of using a woodburner rather than a boiler system is that in theory it can be done without power. A medieval peasant, or carbon-neutral smallholder, armed with a decent sharp axe and a hardwood block, can chop through a 50mm green branch with a single stroke. Whereas logs need saws, which medieval peasants didn't have. I'm not saying I actually do that - I have a chainsaw - but it can be done, which could be appealing for the purist.

Mixed deciduous copse will be far more environmentally sustainable than any form quick growing mono-culture in time you'll have a mini nature reserve on your hands, wood chip boilers are available that are less hassle than log burners, wood chip can utilise a lower grade of wood than log, and while the copse is establishing chip is readily and cheaply available.

The easiest and most sustainable system would system would be a tradional coppice with a mix of species that are suitable for the area almost certianly including ash willow and alder. Does not need fertilising, spraying, expensive machinery to plant or harvest ,is a joy to be in and a boon to nature. The yields maybe lower but 2 hectares should be more than enough for most modest homes although 581m^2 sounds like a huge place.
Establishment maybe slower probably at least 10 years but why not consider existing woodland. There is huge ammounts of underutilised woodland both old unmanaged coppice and comercialy unviable bits of farm woodland that could benefit from management the amount of stored wood in one of these would keep you going for years.
Another thing in favour of this option is the generous grants avaliable for both the establishment and infrastructure(tracks,fencing) and ongoing management.

Posted By: martin samphireThe easiest and most sustainable system would system would be a tradional coppice with a mix of species that are suitable for the area almost certianly including ash willow and alder.

Mmm, I disagree with various issues here. "Traditional coppice" is nice in theory, but neither willow nor alder make particularly good firewood and my primary goal is to dramatically cut external fuel purchases as I switch from oil or LPG to wood fuel. As for diversity, two hundred years ago (traditional enough?) people clearly had no problems with monocultures and provided it's a relatively small scale I don't have a problem with that either. On the subject of wildlife habitat, there are several woods around the property that are all significantly larger than my entire property, let alone the coppice.

On the topic of yields, I have yet to see anybody in this thread post hard figures rather than assertions about yields. Again I invite anybody who feels like it to calculate the average annual yield of useable firewood (for use in a wood stove rather than wood chip boiler) from a one hectare coppice.

Dan

Maybe it doesn't really matter, though. Right now, planting trees just seems to be the right thing to do, regardless of the details.

Ultimately that was my conclusion. Coppice is now in year 3. Hopefully in another 5 years we will be making our first cuts...

There are a few points here to addresss. I cannot give you a yeild for a hectare of coppice for all the various reasons given by joe.e. I havent the experience with in rotation coppice, very few poeple have as it is a practice that had virtually died out in the last centuary. my experience is with restoring coppice in a neglected woodland. the yield here are large (i took nearly 20 t0nnes out of the first half acre (0.2 hectare) and there was loads left over) the woodland i have been restoring was probably last copppiced about 50 years ago.
The issue of monoculture is not nessceraly staightforward, i would not be against planting mostly one species of tree but a woodland managed in this way will naturally become diverse a herb and shrub layer will establish, when it is cut, wild flowers, then brambles will explode untill the cannopy closes again. This diversity is probably part of the reason why a woodland can stay healthy and productive for centuaries or millenia. I think the same applies to having a variety of tree species for example alder whilst not being the best firewood fixes nitrogen in its root nodules distributing it in the autumn leave fall(it is also a very fast grower).
Although it seems unlikely when you first think about it experience indicates woods can maintain coppice yeild without artificial fertilisation part of this is probably that the trees roots go deep and the woody part contian relatively little nutrients. Soil weathering and nitrogen fixing plants and bacteria gradually replenish many nutrients, well developed fungal microrhizia assist the established trees roots to make best use of the available nutrients and droping from birds roostin g in trees and foraging in surrounding field all help. The diversity of species also help, each wiil take up nutients differently and make them available to the others when thier leaves rot down some might be deep rooting others nitrogen fixing others particularly good at uptaking a particular nutrient. You could always return the ashes to the wood if you are worried about depleting a particular nutrient (potassium and most of the micro nutrients are largely left behind in the ash).
On a different subject if you wanted to maximize the fuel potential of your wood you could always bundle the twiggy and sticky parts into faggots. These can be burned in suitable stove i have seen a masonery stove that burnt these it was phenomenaly effective one bundle heated a large space for many hours. I believe they would be good for firing a clay oven or many other uses. It is also good for wildlife to leave piles of brash for habitat, which i mainly do a present.
coppicing to me seems the very epitome of a sustainable, green practice and whilst i'm sure it couldn't provide for all our heating demands at the moment there is alot of scope even just in restoring all the neglected coppice that exists. With moderate sized, well insulated homes and efficient burners I'm sure a family could heat thier home with two hectares or less. I'm certianly confident i can and have plenty to spare.

absolutely, Terry. The fact is coppicing is tried and tested over hundreds if not thousands of years with no evidence of any damage to the woods or soil.

I havent the experience with in rotation coppice, very few poeple have as it is a practice that had virtually died out in the last centuary.

Exactly what I have found - practical experience in establishing a new coppice seems to be close to zero. Without that practical experience I don't think one can compare a new short-rotation coppice with the one you restored which, although neglected, had the benefit of decades to get established and to produce biomass. If I left my coppice for 30 or 50 years to grow freely I'm pretty sure I'd get several dozen tons out of it in one coup, but (a) I can't wait 30 years and (b) subsequent yields would be much smaller if you were making coups every 5 years. My coppice was planted in early 2005 with the plan being to cut every five or six years, starting with an initial harvest in year eight. That's a very different proposition to harvesting a coppice that has been left to its own devices for half a century. Ultimately, I see that as being one of those things that you can only really know by doing. Nobody here seems to have "done" new coppice although there's plenty of conjecture and opinion. I'll let you know in 5-6 years what the reality is like as far as production is concerned.

What I don't have a good feel for is the demand side. How many dry tonnes of firewood per year would one need to heat the mythical "average" house with middling insulation and draught proofing? I seem to remember the BTCV Woodlands book suggesting that 7 to 9 tonnes would be required every year.

Dan

<blockquote><cite>Posted By: Terry</cite>Oops, sorry Martin, got distracted and didnt finish what I was going to ask.
Would your suggested faggots not be better left to replenish the soil? Maximising fuel potential in this way could end up as a short term gain, but result in big long term loss??</blockquote>

Yes, you're right But i dont think that depleeting the soil is the main issue. I think it is good to leave piles of brash for habitat.If i was merely sugesting ways of of maximising the fuel yeild for those who are worried about such things. If yor main reason for coppicing is conservation then leave the brash and even some logs. I'm sure that in the past people would have used every scrap of wood for something and there is no evidence of any damage to the woods.

Dan- your coppice cycle of 5 years is very short. i would have thought you would do better to double that or more like 12 or 15 years if your primary aim is firewood logs dependi. I guess that with that short a rotation you would be in danger of stressing the trees, the shortest traditional cycle would be 7 years. Quite apart from giving the trees time to recover and return energy to thier roots which they use in the first two or three years of regrowth, five years is required for the canoppy to close, if this does not happen the brambles will not be naturally controled by shading and this will make your work much harder. Eight years establishment would probably be enough but i dont think you should expect a large harvest from that though.
If you only have just over a hectare why not cut about 0.2 hectare every other year this would give you a ten year cycle if you cut the first coup at eight years this probably wont give you much but by year 12 you might be getting a usefull amount. You dont really want to cut areas much smaller than this as shadin from surrounding trees cause poor regrowth. This would allow one year felling followed by the following year carrying out what you have felled when it has lost some of its moisture and is not so heavy.